Background: To measure the direct effects of pre-operative magnetic resonance neurography (MRN), and analyze the procedure and clinical outcomes of the percutaneous endoscopic interlaminar discectomy, in order to demonstrate the feasibility and safety of the interlaminar approach.
Methods: In this study, 127 patients who underwent percutaneous endoscopic lumbar discectomy (PELD) and were followed up by more than 12 months, were retrospectively evaluated. The pre-operative demographic data were collected. In addition, the coronal scan and the reconstruction of the lumbosacral plexus were examined to measure the distance between the nerve root and the dural sac at the coronal plane. Furthermore, the post-operative and pre-operative visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were compared.
Results: The mean and minimum values of distance T between the nerve root and dural sac of L5/S1 to L2/3 on the operation side of the MRN images were all larger than 7.3 mm which is the diameter of the working canal. During the follow-up, VAS and ODI data improved significantly compared with their corresponding pre-operative scores (P<0.01). Regarding the post-operative complications, there were 2 (1.57%) cases of hypesthesia and 3 (2.36%) cases of neuropathic pain, which were transient and alleviated in 3 months. In addition, there was 1 (0.79%) case of intervertebral space infection and 1 (0.79%) dural tear. No relapse of disc herniation and iatrogenic instability occurred by the end of the last follow-up.
Conclusions: The MRN indicates that the incidence of herniated disc impingement increases over the distance between the nerve root and the dural sac, thus making the interlaminar approach more suitable for the treatment of herniation. The procedures and clinical outcomes of the IL-PELD demonstrate the safety and advantages of the interlaminar approach.
Keywords: Interlaminar endoscopic lumbar discectomy; lumbar disc herniation; magnetic resonance neurography (MRN).